A resin composition capable of forming a transparent membrane having light transmission is widely used in formation of optical instruments.
A UV curing type resin composition having an acrylate type material as a main component disclosed in Patent Literature 1 is herein widely used as a resin composition.
Organic materials of acrylate type materials and the like however, have, problems of being difficult in providing sufficient hardness. There is therefore a problem such as follow is caused, when the acrylate type material is used for a protective layer and the like provided on the surface of optical instruments, in some cases, sufficient scratch resistance cannot be obtained.
To solve these problems, Patent Literature 2 discloses an inorganic type resin composition containing inorganic materials as a main component and further having the patterning ability. Use of the inorganic type resin composition described above can provide sufficient hardness, thereby forming a transparent film excellent in scratch resistance when used for a protective layer of optical instruments and the like.
However, the inorganic type resin composition described above is, insufficient in heat resistance and generates a problem of which exposure to high temperature in a manufacture process of optical instruments and in their use results in reduction of transparency by discoloration and decrease of functionality.
For example, an optical instrument such as a touch panel uses in some cases a transparent electrode as an electrode. Heretofore, such a transparent electrode is generally heat-treated around 230° C. in manufacturing process. However, for example, to reduce a resistance value of the transparent electrode, a high temperature treatment (annealing) step at high temperature of 250° C. to 300° C. is performed to make the electric current sufficiently flow through a thin wire along with thinning of the wire and the film thickness of the transparent electrode in recent years. With a resin film using a conventional inorganic type resin composition, even if the composition do not cause yellowing, peeling and poor adhesion in heat treatment at 230° C., the composition becomes to have a problem of causing yellowing and poor adhesion in the heat treatment step at high temperature of 250° C. to 300° C.